“No, Rob, don’t get that wrong.” Regulo’s voice showed an odd mixture of pride and reproof. “You are a better construction man than Keino will ever be. I picked you for the hard job, not the easy one. How far have you thought it through?”
That was a touch of the old Regulo. Rob wondered if his exhausted brain had jumped to a wrong conclusion about the old man. Well, a few more minutes and he could collapse.
“Just the general idea. It starts with the Spider again. Now it’s spinning a different kind of web. Rockets are wrong. That’s sitting there in your desk as we talk, but I didn’t follow it far enough. I should have known you wouldn’t stop with the beanstalk, that just gets us up and down from Earth. You wanted a way of moving materials around the whole System without using drives. And the Spider could give you that.”
Rob paused for a few seconds, to examine again his left forearm. The pain was mounting, from acute to intolerable. He checked once more that the power input was disconnected. No doubt about that. He massaged the arm again with his right hand, unable to imagine any possible explanation. He motioned to Corrie to use the injector a second time. What was the maximum permitted dose?
“Spin another cable,” he went on. “Make it like the beanstalk, with superconducting cables and drive train attached to the load cable. This time, put the powersat at the center of the cable, with an equal length on each side of it. Fabricate it in space, but don’t ever plan to fly it in and tether it. Leave it out near the orbit of Mars, or in the Belt, or in near Earth — key places in the System. Then start it rotating about its center, like a couple of spokes on a wheel. I assume that you began with just a couple of them, one in the Belt and one near Earth?”
Regulo nodded calmly. He had finished fiddling with the control panel and now seemed oddly relaxed. “We started with two. That’s just the beginning. The more you have, the better the efficiency of the whole operation. I’ve been thinking we’d build about five thousand of them through the Earth-Belt region.”
“You could handle that many?”
“With Sycorax? Easily. We can track that number, and more — there are millions of orbits in the data banks already. This is just a few extra ones.” Regulo’s tone was that of a patient teacher. “I’ve told you before, Rob,” he went on. “Think big. The System’s a big place. You have to scale your thinking to match it.”
Rob would normally have found the conversation totally fascinating. Now it felt increasingly surrealistic. Was Regulo on his own kind of tranquilizers? The image of Morel’s body had gone from the screen, and with it any interest by Regulo in Rob’s accusation. He seemed happy to talk engineering.
Apparently Corrie was having the same reaction. “Don’t you two have any feelings?” she broke in. “Joseph Morel is dead, Caliban seems to have gone mad, and you sit there talking about spinning beanstalks. What about the Goblins, Rob? First you tell us there are children in Morel’s lab. Then you start talking about something completely different.”
As she spoke she realized that she was not getting through to them. They both ignored her. Some invisible cord of tension bound them to each other, some other level of communication was taking place deep below the surface.
“So how would you work it, Rob?” said Regulo. His bright eyes were fixed on the other man’s pale face.
Rob hesitated, but the urge to explain was too strong.
“Just as you did. You have a rotating cable out in a free orbit — thousands of kilometers of it.” He leaned forward, at the same time as Regulo moved his chair farther away from the desk.
“Now suppose you want to move a space pod from the Belt to the Moon,” Rob went on. “You make it rendezvous with the center of the cable, where the powersat sits. The center of mass of the cable would be moving in a free-fall orbit, travelling about the sane speed as the pod, so you use hardly any reaction mass to make the rendezvous. You don’t need much acceleration from the pod’s drives, either, just a fraction of a gee will be enough. Once you have the pod at the middle of the cable, you let it move out along the drive train. As the pod moves from the center it feels a centripetal acceleration. You need to use the drive train on the cable to restrain it. When it reaches the end of the cable, you release it to move in free fall. You’ve given it a big velocity boost. But the trouble from the point of view of a human on the pod is the acceleration. Out at the end of the cable, it’s huge. I looked at a couple of examples. A cable four thousand kilometers long, with end velocity of twenty-four kilometers a second, would give thirty gees at each end. That’s what killed the Goblins.”
“They were unlucky.” Regulo had moved his chair farther and farther from the desk, until it was almost back to the wall. “If you like, you could even say that it was Caliban’s fault. He received no inputs on space operations for passenger transfer, and intelligence can’t replace experience. He put the space pod to a cable rendezvous with a cargo Slingshot — one with high accelerations, never intended for people.”
“Do you have Slingshots for passengers?” Rob moved forward right up to the desk.
“We built the first two, just a month ago. I could find out which cable your Goblins used easily enough, by checking the angular momentum of all of them. Each time we use a Slingshot we naturally increase or decrease its angular momentum.” Regulo stood up, his back to the wall. “We lose angular momentum when we throw a cargo in toward the Sun, and pick it up when we catch something thrown in from Mars or the Belt. Provided we move the same mass of materials in and out, the whole system balances — just like the beanstalk back on Earth. I would have given you details of the Slingshot as soon as we had Lutetia under control. You’ve got the idea, but you’ll be surprised when you see how much we can cut off transit times.
“Well, enough of that.” Regulo’s voice changed in timbre, becoming gruffer and more intense. “The Slingshot was used in a way I never expected. It killed two of the `Goblins,’ if you’re correct. But what about the rest of it? Joseph was secretly performing some kind of social experiment here, that’s what you’re telling us. If he had a self-sustaining colony they would have been through many generations in thirty years. It makes me wonder what type of social structure they could have evolved. Did Joseph tell you what he was trying to achieve in his colony, before Caliban got him?”
“Not a thing.” Rob stood up. “Morel didn’t intend to tell me anything. He was supremely logical, and logical people don’t bother to explain things to a dead man. I had one other factor to consider while I was locked in that lab. Morel wasn’t an anthropologist. He didn’t have the slightest interest in social structures. He never told me what he was doing. But you see, Regulo, I know it anyway.”
“Aye.” Regulo’s voice was as calm as ever. “I was afraid of that. The second that you came in here, I thought that the game might be over.”
He waved a thin hand at the control panel. “While you were talking, I gave the signal for the maintenance crews to make emergency departure from Atlantis. They’re clear now, wondering what the devil is going on. See the ship?”
On the display, a large freighter hovered beside Atlantis. Near it, filling the screen, the swollen balloon of Lutetia hung, its surface white-hot and smoking with escaping volatiles.
“I have to ask you one more thing,” Regulo went on, “though I think I know the answer. I suppose that it would be a waste of time to offer you part of Regulo Enterprises?”
Rob shook his head. The movement sent a flare of pain down his left arm.